Artificial kidney system



Jan. 24, 1961 v c. R. BROMAN 2,969,150

ARTIFICIAL KIDNEY SYSTEM v Filed Jan. 25, 1957 2 Sheets-Sheet 1 FROMARTERY TO vm N 6' r E. roman y as IIQENTOR.

Jan. 24, 1961 c. R. BROMAN 1 2,969,150

ARTIFICIAL KIDNEY SYSTEM Filed Jan. 25, 1957 2 Sheets-Sheet 2 Cyrus P.fireman INVEN TOR.

United States Patent ARTIFICIAL KIDNEY SYSTEM Cyrus R. Broman, Evanston,111., assignor to Baxter Laboratories, Inc., Morton Grove, Ill.

Filed Jan. 25, 1957, Ser. No. 636,269

5 Claims. (Cl. 210-321) This invention relates to an artificial kidneysystem, and more particularly, to a structure adapted to receive acoiled, artificial kidney and provide a source of dialyzing fluid forthe artificial kidney.

The artificial kidney component of my system may take the form of aflat, elongated, perforate housing, such as non-toxic screening, woundupon itself to form a cylindrical coil. Contained within the screenenvelope are two tubular septa, generally constructed of a cellulosicmaterial so that they can conduct blood but permit the dialysis ofdeleterious substances from the blood such as urea.

It is, therefore, an object of my invention to provide a completeartificial kidney system capable of being interconnected into the bloodcirculatory system of a patient whose own kidneys are incapable offunctioning properly. Another object of my invention is to provide anartificial kidney system characterized by low cost, portability, andease of use. Yet another object is to provide a system having anarrangement of elements permitting substantially continuous use of thesystem during a prolonged dialysis of a patients blood irrespective ofthe need for replacing the artificial kidney or dialyzing fluid. Otherobjects and advantages of my invention will be explained in conjunctionwith the accompanying drawing in which Fig. 1 is a perspective view ofthe artificial kidney system of my invention wherein certain internalelements of the system are shown in dotted line; and Fig. 2 is anenlarged fragmentary portion of the elements shown in dotted line inFig. 1.

Referring now to the drawing, and in particular Fig. 1, the numeralgenerally indicates the frame which supports the various elements of theartificial kidney system of my invention. Frame 10 is seen to consist ofan interconnected arrangement of tubular members providing a horizontalplatform 11 from which depend casters 12, permitting the frame to bewheeled from place to place and patient to patient very conveniently.

Frame 10, in addition to the horizontal platform 11, includes a verticalportion 12 which accommodates an instrument panel 13 and a handle 14..In the preferred embodiment, one element of vertical portion 12 isextended upwardly to provide a standard 15 for the mounting ofparenteral solution equipment used in the operation of an artificialkidney system.

Mounted on frame 10 and spaced from horizontal platform 11 is tank 16.Intermediate tank 16 and horizontal platform 11 and mounted on platform11 is circulating pump 17. Circulating pump 17 has its outlet connectedto the central base portion of cylindrical tank 16 as at 18 and theinlet of circulating pump 17 is also connected to the base of tank 16but at a point spaced from the pump outlet connection, the pump inletconnection being designated 19.

Mounted in tank 16 is receptacle 20. In the embodiment shown, theinner-central base of tank 16 is provided with a vertical riser 21 whichis threaded as at 21a at its nonconnected end. Receptacle 20 is ofgenerally cylindrical configuration and is provided with an axialopening in the base thereof as designated 20a, and which is internallythreaded so as to mate with threaded portion 21a of vertical riser 21,which thus rigidly but removably supports receptacle 20 in tank 16.

Contained within receptacle 20 is an artificial kidney generallydesignated 22 and which can be seen in larger scale in Fig. 2. Aspointed out above, the artificial kidney 22 intended for use in myartificial kidney system includes 2 flat cellulose tubes envelopedbetween non-toxic fiber glass screens, the tubes and screening formingan assembly that is tightly but uniformly coiled about itself andprovided with suitable end connections leading from and to the body ofthe patient to be treated. These connections are indicated in dottedline also in Fig. 1 and the portions of the blood circulatory system towhich they are connected are referred to.

Tank 16 is provided with a hinged transparent cover 23 which permitsvisual checking of the operation of the artificial kidney system at anytime. If either of the above-mentioned septa should rupture, thedialyzing solution circulated by pump 17 would become discolored and thesystems operation discontinued.

A second horizontal platform 24 is provided spaced from horizontalplatform 11 which accommodates a pair of pumps operating on the bloodconduits leading from and to the patient, the pumps being designated 25.

Mounted on the side wall of tank 16 is heater 26 having element 260extending inwardly of tank 16. The control for heater 26 is a toggleswitch mounted on instrument panel 13 which is also provided with asignal light indicating that the heater is on. In like fashion a controland signal light is provided on instrument panel 13 for circulating pump17. Instrument panel 13 also accommodates a dial thermometer connectedwith a thermometer mounted in tank 16 as at'27.

Also mounted on horizontal platform 11 is drain pump 29, an inlet towhich is connected to tank 16 as at 30. The outlet from drain pump 29 isprovided with a hose 31 that can be conveniently positioned on any drainfacilities such as a sink or the like. It is considered desirable tohave a drain pump separated from the circulating pump since, in thecourse of the ordinary usage of my artificial kidney system on aparticular patient, it is necessary to replace substantially all of thecirculating fluid at least once. During the drain of the first charge ofcirculating fluid, it is still possible to keep the kidney in operationsince only a small quantity of fluid is circulated by the circulatingpump.

Tank 16 is also provided with an air inlet as at 32 which permitsaeration of the circulating fluid.

Referring now to Fig. 2 which shows in enlarged form the internalportion of tank 16 and, more particularly, receptacle 20, it is to benoted that receptacle 2% is generally cylindrical in configuration andis provided with 2. depending axial neck portion 2012 which isinternally threaded as at 20c. Neck 20b is thereby adapted to be mountedon vertical riser 21 and therefore be communicated with the outlet ofcirculating pump 17.

Received within receptacle 20 is artificial kidney 22 which has a screenenvelope 33 enclosing spaced septa 34. Kidney 22 is mounted on a core 35which conveniently can take the form of a stainless steel cylinder suchas a can. Receptacle 20 is charnfered or outwardly bowed or dished as at36 to permit the ready inflow of dialyzing fluid from circulating pumpwhich might otherwise be obstructed by the contact of the base of can 35with the inner base of receptacle 20. The side wall of receptacle 20 isprovided with a pair of annular indentations designated 37 which are sopositioned with respect to the base of receptacle 20 that when kidney 22is received therein, indentations 37 will press against that apeaaeoportion of kidney 22 carrying septa 34. Thisresultsin.

external to the outer convolution of kidney 221 The flow of dialyzingfluid istherefore directedalo'rig" a path parallel to the axis ofreceptacle 20. At the same time it permits ready access to the outerwall ofkidney 22 adjacent the top thereof to permit a convenientgripping surface for removal of the kidney from receptacle 20. It is tobe noted from a comparison of Figs. 1 and 2 that; receptacle 20 whenkidney 22 is received therein has a comparatively small unfilled volumecompared to tank 16:

Receptacle 20 is partially closed by a circular ring- 38- having acentral opening 38a and which is bolted to receptacle Zfl by bolts 38bwhich are inturn securedby wing nuts 33c. Annular ring 3S is ofsufllcient width to overlap at least one soil of kidney 22 to restrictthe flow of dialyzing fluid through the coils of kidney 22 rather thanallow bypass around kidney 22. Interspersed between ring 38 and the toplip of receptacle 2G is gasket 1%, insuring no leakage of dialyzingfluid through that joint.

Operation To operate the artificial kidney system of my invention,

the tank unit which has a capacity somewhat in excess of 100 liters isfilled with a suitable dialyzing liquid. Such a fluid might include thefollowing constituents per liter:

0.4% invert sugar Bactic acid to adjust pH to 7.4

This fluid is circulated by pump 17 so that it enters the central baseof receptacle 20, overflows the top and is returned through connection19 to circulating pump 17. The temperature of the liquid is maintainedby heater 26 to about 39 C. and the solution is aerated by using aboutcarbon dioxide in oxygen.

The kidney 22 is then inserted into the receptacle 2t) and septa 34become fully wetted. An electrolyte solution is then pumped throughsepta 34 by establishing connections through the conduits thateventually will lead to the vein and from the artery of the patient.When the septa are fully wetted, approximately 6 liters of isotonic(i.e., 0.7% NaCl) electrolyte should be pumped into the septa. Ifdesired, the septa may be tested for leaks by pumping about 100 cc. ofheparinized blood through them, followed by more saline. To the lastquantity of saline, a small quantity of heparin should be added.

Ring cover 38 for receptacle 20 is then applied and wing nuts 38c aredogged down to insure a tight fit of kidney 22 within receptacle 20.

The patient is cannulated about an hour prior to conmeeting myartificial kidney system to his circulating system. This minimizes thechances of clotting at the points of cannulation. The vein cannula isfirst inserted, followed by the arterial cannula. The artificial kidney22 is then primed with about a liter of citrated bank blood which can beconveniently mounted on standard 15. The patients blood is then causedto flow through the kidney 22, the rate of flow being determined byvisual examination of the flow in an air-trap-filter-drip unit which isinterconnected into the vein conduit. The drip unit should be mounted ina vertical position and can be conveniently suspended also from standard15.

After about two to three hours of circulation of the patients blood, itbecomes necessary to change the dialyzing fluid. This is done simply byactuating drain pump 29 without stopping circulating pump 17 or the flowof blood in kidney 32. The entire unit can be drained without danger tothe patients life. However, in prac- 4 tice a small quantity ofdialyzing fluid is not drained which permits the kidney 22 to remainimmersed in fluid throughout the dialysis which may last six hours ormore, The comparatively small unfilled volume of receptacle 20 whenkidney 22 is mounted therein, in comparison with the volume of tank 16,permits substantial drainage of tank 16 without exposing the exterior ofsepta 34 to air which would halt the dialysis and possibly stress septa34. Once it is drained, a new charge of dialyzing fluid can be added totank 15, and the remainder of the dialysis of the patients bloodcontinued.

At the end of the dialysis, the used artificial kidney can be removed bymerely removing cover 38 and lifting out kidney 22. Drain pump 29removes all fluid and, after the tank 16 is rinsed, it is ready for useon another patient. The kidney 22 along with its connections andfilter-dripair-vent units are disposable, so no cleaning is required forthem. The blood circulating pumps 25 operate on the exterior of tubingso no cleaning is required for them either. The ease of removal andreplacement of kidney 22 in the system of my invention permits a blooddialysis to continue without substantial interruption even though aseptum should fail, and thus the kidney 22 would have to be replaced inthe course of a dialysis.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be inferredtherefrom.

I claim:

1. In an artificial kidney system, means for circulating a dialyzingliquid, a cylindrical receptacle for a coiled artificial kidney, saidreceptacle being operatively interconnected in said circulating means,said receptacle having an annular indentation intermediate its endswhereby said kidney is tightly but readily-removably received in saidreceptacle, and an annular ring cover mounted on said receptacle wherebysaid cover and said indentation co-operate to cause all dialyzing liquidto flow between the coils of said kidney along the entire lengththereof.

2. An artificial kidney system comprising a frame, wheel means on saidframe permitting the frame to be transported, a tank mounted on saidframe, a circulating pump mounted in said frame, the outlet of said pumpbeing operatively connected to central base of said tank and the inletof said pump being operatively connected to the base of said tank at apoint spaced from said outlet connections, a tank discharge pump on saidframe having its inlet connected to the base of said tank, a cylindricalreceptacle removably mounted above the central base of said tank butwithin said tank and communicating with said circulating pump outlet, anartificial kidney removably mounted in said receptacle, said receptaclehaving a larger internal diameter than the outer diameter of saidkidney, permitting ready removal of said kidney from said receptacle andretention of dialyzing fluid from said circulating pump when saiddischarge pump is operative to drain said tank, said kidney comprisingan elongate, perforate flat envelope housing a spaced pair of flatpermeable tubular septa, said envelope being wound upon itself to form acylindrical coil with connection means to the ends of said septaextending outward of said coil, said receptacle having a pair of annularindentations in the side wall thereof. so positioned as to compress theseptal portions of said kidney, a removable cover for said receptacleprovided with a central opening whereby fluid from said pump is causedto flow upward through said receptacle and kidney and substantially nofluid bypasses the septal portions of said kidney.

3. In an artificial kidney system in which a flat septum is wound onitself to provide a blood dialyzing conduit, a septum-receivingreceptacle having an open top and a connection in the bottom thereof forintroducing dialyzing fluid therein, said receptacle being generallycylindrical with the side wall thereof having an annular indentationintermediate the ends thereof and of a height less than the width ofsaid septum.

4. The structure of claim 3, in which the said indentation is so locatedalong the height of said receptacle as to abut the central portion ofthe width of a septum received in said receptacle.

5. The structure of claim 4, in which a plurality of indentations areprovided corresponding to a similar plurality of superpositioned woundsepta received in said receptacle.

References Cited in the file of this patent UNITED STATES PATENTS2,720,879 Gasca et al Oct. 18, 1955 6 OTHER REFERENCES Krainin:Cross-Dialysis Proceedings of the Society of Experimental Biology andMedicine, vol. 82, No. 3, March 1953, pp. 515-518.

Renal Robot, Jr., Journal of the American Medical Association, vol. 155,No. 10, July 3, 1954, pp. 26-27.

Kolfi et al.: Further Development of a Coil Kidney," Journal ofLaboratory and Clinical Medicine, vol. 47, No. 6, June 1956, pp.969-977.

